The Metropolitan police is investigating incidents of coin-throwing by West Ham supporters at Chelsea, with the Football Association expected to launch its own inquiry once the referee's report has been filed.

Chelsea's club captain John Terry was struck by coins as he warmed up on the touchline during the first half, the centre-half eyeballing the away support before turning his back on them to bend over and stretch in the corner. Further objects were thrown at Frank Lampard as he celebrated with Terry in front of the visitors' section after opening the scoring.

"I wasn't hit by anything," Lampard said. "I went quite close to the West Ham fans but that was the natural curve of my run." The fourth official, Howard Webb, was aware of the matter and later instructed the substitutes from both teams to warm up at the other end of the pitch in front of the home support.

No arrests or ejections were made at the fixture but Chelsea have confirmed they are to continue scrutinising closed circuit television footage in an attempt to identify those West Ham supporters involved.

"West Ham will be working with Chelsea to investigate the reports of missile throwing during Sunday's game at Stamford Bridge," said a spokesman for West Ham. "Any individual found to have acted in an inappropriate way will have to face the consequences of their actions, including the possibility of a ban from attending future matches."